There is a great need for portable low power volatile organic compound (VOC) sensors for monitoring VOC emission in today's industrial scale natural gas production. See, for example, Karion et al., “Methane emissions estimate from airborne measurements over a western United States natural gas field,” Geophysical Research Letters, vol. 40, pgs. 1-5 (August 2013) and J. Peischl et al., “Quantifying sources of methane using light alkanes in the Los Angeles basin, California,” Journal of Geophysical Research: Atmospheres, vol. 118, pgs. 4974-4990 (May 2013).
Semiconductor metal oxide based gas sensors have great potential in such applications due to their low cost and portability. However, the power consumption of such sensors is relatively high (e.g., greater than 50 mW), which hinders their application in continuous monitoring with battery power in a service time scale of years. For instance, microelectromechanical (MEMS)-based membrane gas sensors, which are currently the most advanced and of the lowest power consumption, still consume from about 6 mW to about 20 mW of power. The high power consumption of these sensors is mainly due to the requirement of operating the sensors at elevated temperatures (e.g., from about 300° C. to about 400° C.) during gas sensing in order to achieve reasonable sensitivity.
Therefore, improved low-power gas sensors would be desirable.